Pump



G. A. WAHLMARK Sept. 23, 1952 PUMP 4 Sheets-Sheet? Filed Dec. 1'7, 1945 66%;w [KM My mags Filed Dec. 17, 1945 4 Sheets-Sheet 5 Sept. 23, 1952 G. A. WAHLMARK 2,611,318

PUMP

Patented Sept. 23, 1952 PUMP Gunnar A. Wahlmark, Rockford, Ill., assignor to Sundstrand Machine Tool 00., Rockford, 111., a corporation of Illinois Application December 17, 1945, Serial No. 635,455

12 Claims. (01. 103-2) 1 This invention relates to a variable displacement pump. It is the general object of the invention to provide a new and improved pump of this type.

7 parent .from the followingidetailed d scription a preferred form of the invention.

taken in connection with the accompanying drawings in which:

Fig. 1 is a longitudinal central section through It is another object of the invention to provide Fig. 2 is a section approximately along the a new and improved variable displacement pump line 2-2 of Fig. 1. having a plurality of piston and cylinder devices Fig. 3 is a fragmentary section alon the line and a plurality of independent outlet ports to- 3-3 of Fig. 1. gether with driven valve mechanism for con- Fig. 3a is a fragmentary section along the line trolling the flow of fluid to the discharge ports. 311-311 of Fig. 1.

Another object is to provide such a pump Fig. 4 is a section along the line 4-4 of Fig. 1. adapted to supply fluid equally distributed to a Fig. 5 is a fragmentary section along the line plurality of outlet ports and without detrimental 5-5 of Fig. 1. pulsation of the fluid pressure at the ports over Fig. 6 is a fragmentary section along the line a wide speed range. 6-6 of Fig. 1.

Another object is to provide a variable dis- Fig. 7 is a section along the line 1-1 of Fig. 1. placement pump of the Wobbler type having a 8 is an e larged fragmentary section plurality of piston and cylinder devices, a pluthrough the servo control with the Parts 1 5 I ralityof discharge ports, and valve mechanism tioned to effect a decrease in the outp o th for controlling the flow of fluid through the pump. pump, said valve mechanism including a plate- Fig. 9 is a similar view showing the parts in a like valve member having an annular row of Position of q r u ports therethrough, one associated with each Fig. 10 is a similar view showing the parts in cylinder, and means for efiecting a, gyratoyy position to effect an increase in the output Of movement of said valve so that cylinders are cone pu p. nected in sequence t th corresponding While the invention is susceptible of various chargeportg modifications and alternative constructions, it is Another object s t provide a i t t pump shown in the drawings and will hereinafter be it an ih pump for supplying fluid under described in a preferred embodiment. It. is not pressure, some of which is utilized to lubricate intended. w t at the inVention is to be the pump pistons d t prevent leakage of t limited thereby to the specific construction disfiuid pumped by th piston pump, closed, but it is intended to cover all modifica- Another object of th i nt is t provide tions and alternative constructions falling within such a multiple piston pump adapted particularly the Spirit d s ope of the. invention as defined for handling a fuel, such as gasoline, which has in the appended liieimslittle or no lubricating properties, and to include AS illustrated in the drawings, e i ve t on an auxiliary pump handling a lubricating liquid comprises generally a hollow casing having a such as 11 some f which is used to prevent somewhat tubular section I i] and an end section leakage of the gasoline, and furthermore is fed I cylinder: bloc}? having a plurality of 0571111 into the gasoline through normal leakage paths 40 der bores I3 In which plstons it are reciprocable, of the piston pump so as to provide a lubricant a drive shaft l6 rotatably mounted in the casing, fo the pistons and valve mechanism of that a Wobbler device I! for converting rotary motion pump. It is a particular object of the invention the shaft mto reciprocatpry movement of the to provide a fuel pump of this type with means plstqns an annular i valve for 9 for adjusting the pressure of the liquid handled i5 trolling the flow of flllld to and from the cylmders, an inlet port 19 and a plurality of discharge by the auxlhary pump so as to vary the amount ports 2!}, one for each of the cylinders l3. of lubricant fed into the fuel. Y Thevcylinder block '2 n u v A further object is to provide a new and imls ge era y anm-I m I form and has an integral flange 2| positioned Pmved control mechemsm for a varleble between the casing sections In and II, the casing placement pump, and more partlcularly a servo ti n and flange being secured together by a '4 type of control mechanism of new and improved plurality of screw devices 22. The cylinder block v construction. I p i p} is, provided with a cylindrical recess in its right Other ob ects and advantages W111 become aphand end (Fig. 1) to form a cylindrical valve chamber 23 having opposed; parallel faces 24' and I cylinder bores.

25. It is in this valve chamber and against these faces that the valve I8 is positioned.

The shaft I6 is rotatably mounted in the casing by means of a roller bearing 26 and a ball bearing 21 at the left hand end of the casing, and by means of a roller bearing 28 supported in the cylinder block I2. The Wobbler device comprises an inner ring member 29, which .is pivotally mounted on the shaft I6 by means of a diametrically extending pin 30 (Figs. 1 and 2-) and is operable by means of a piston 3| in a cylinder 3|. A piston rod 32 is connected by a pivot pin 33 to the inner ring 29 .of the Wobbler. The Wobbler includes an outer ring 34 carried on the inner ring by means of a ball bearing 35, and arranged with a flat end face 36 in position to engage the adjacent convex ends of the pistons I4. 1

The pistons I4 have relatively larger portions I4, which engage in larger portions I3 of the This provides each piston with an annular surface 3! which functions in amanner hereinafter more fully described.

The how of fluid to and from the cylinders I3 is controlled by the valve I8 which as illustrated in the drawings is a wheel-like member, havin a hub portion 40, an annular rim 4|, and a plurality of spokes 4 I The valve is positioned with its annular rim portion 41 in the cylindrical valve chamber 23 so as tobe intermediate the adjacent ends of the cylinders l3 and the alined discharge ports 20 opposite thereto. The valve is given a gyratory movement by means of an eccentric pin 42 which is carried on a shaft 43 positioned in axial alignment with the shaft I6 and connected thereto by means of multiple splines '44 and a ring 45 which .is secured to the shaft I6 by a tion of the valve chamber .23 from the inlet port I9 through a plurality of ports 48 (Fig. 4') which extend radially through the rim portion 4| of the valve. With the parts as illustrated in Fig. 4, fluid is thus being supplied to the right hand cylinders I3 and is being discharged from the left hand cylinders. The valve ports 41 are alined with the cylinder ports and discharge ports when in their wide open positions.

In order to maintain the ports 41 of the valve continuously connected with the adjacent cylinders l3, means is provided for preventing substantial rotary movement of the valve I8 during operation of the pump. As illustrated in the drawings a pair of shafts 55 (Figs. 1, 3, and 6) are rotatably mounted in sleeves 50 secured in a bushing secured within the casing section II. The shafts 58 are parallel to the shaft 43 and spaced equi-distantly therefrom above and to one side of the shaft 43 as shown in Figs. 6 and '7. These shafts 5i! carry eccentric pins 52 which engage in bores 53 in the valve I8 spaced equidistantly from the central bore 48. The pins 52 and 52 have the same eccentricity with respect to the shafts on which they are carried, with the result that the pins 52 serve as idlers to hold pump casing IO.

4 the valve I8 against rotary movement during the gyratory movement thereof.

In the form of the invention herein disclosed there are 24 cylinders I3 and 24 discharge ports 2i However the pump has but 8 outlet ports 54, each one communicating with 3 of the discharge ports 25. The discharge ports 20 are connected in groups of 3 by means of annular passages 55 in the casing section II, eight in number. Each of the annular passages is connected to three discharge ports, one hundred and twenty degrees apart, as shown in Figs. 1 and 7 by means of recesses .58. B connecting three equally separated discharge ports to each outlet port, pulsation of the fluid pressure at each outlet port is minimized over a wide range of speed.

During operation of the pump the pistons I4 are moved through their pressure strokes by means of the Wobbler It. To return the pistons through their suction strokes the annular surfaces 31 on the pistons serve as auxiliary pistons and are subjected to a fluid under pressure supplied from an auxiliary pump 60. The enlarged portions I3 of the cylinders are all connected together by means of an annular chamber 5| in the cylinder block I2. The auxiliary pump 60, which may be of a well-known rotary or gear type, has an outlet port 62 communicating with the chamber 5|. An inlet port 53 for the auxiliary pump communicates with the interior of the casing section ID, which is kept filled with a lubricating fluid such as oil.

The auxiliary pump comprises casing members 2 and H3 which are secured to a transverse portion I I4 of the cylinder block 2| by a plurality of screws 5. Apinion 65 is pinned on the shaft 43 and engages with an internal ring gear 66 located within a cylindrical chamber 67 'in the casing of the pump. A crescent shaped member 68 is integral with casing member H2 and sepa-' cylinder block, so as to urge the control memberv toward the left in Fig. 1 or toward a position placing the wobble plate in neutral. Thus without a fluid under pressure acting on piston 3|, the wobble plate is maintained in neutral position by the control member Ill. The movement of the wobble plate from its neutral position is controlled by the pressure of the fluid admitted to the cylinder 3| through a tube 14 which extends axially through portions of the shafts I5 and 43, and which at its right hand end (Fig. l) is supplied with fluid from the auxiliary pump 43 through intervening control means hereinafter more fully described.

Adjustment of the output volume of the pump is accomplished by adjusting the angular position of the Wobbler I! with respect to the axis of the shaft I6. Preferably this is accomplished by a servo-control mechanism of the type illustrated in Figs. 1 and 8 to 10. In this mechanism a lever is pivotally supported at 8| on a casing 82 which houses the control and is secured to the The lower end 83 of the lever 88 bears against the exposed end of the tubular control member In (Fig. 1). The upper end of the lever is forked or bifurcated.

The casing 82 has alined bores 84 and 85 theremember I I2.

in, positioned parallel to the-shaft I6. A piston 86 is slidably mounted in thebore 84 and a sleeve valve 81 is slidable in the bore 85. The right hand end of the bore 85 communicates with a larger bore or cylinder 88. An opposed piston 89 is slidable in cylinder 88 and has a tubular stem 98 slidable in the sleeve 81 and through a bushing I I8 fixed in the right hand end of bore 85. A reduced portion 9I of the stem 98 extends into the sleeve 81 and carries a piston valve 92 the positions of the sleeve with a passage 95 (Fig. 1) leading 'to an annular recess III in Radial ports H6 in shaft 43 connect the recess II I at all times with the passage 81. At one end the rod 96 extends into a conical recess 98 in the adjacent end of the piston 86 and engages the bottom of said recess. The V other end of rod 96 passes through a bore in the stem portion 9| and is pressed into a bore II! p in the piston 89.

The left hand end of the bore 84 is connected to a pump outlet port 28 by means of a passage connected by a passage I 88 to the annular chamber 6| (to which the outlet of the make-up pump 68 is connected by passage 62) so that the right hand end of the sleeve 81 is at all times subjected to the constant pressure of that pump.

The left hand end of sleeve 81 engages'the upper bifurcated end of the lever 88. A plurality of radial ports I8I connects the left hand end of the bore 88 to the interior of tubular stem 98, which in turn communicates, by means ofthe opening through the sleeve 81 and a passage I28, with the pump casing I8 which serves as a tank or reservoir. A passage I82 connects the right hand end of cylinder bore 88 with a cylinder I83 of a pressure control device in the form of a piston I84 which is slidable in said cylinder and is actuable by a suitable connection I85'to an actuator I86.

For the purpose of maintaining a uniform pressure on the control fluid in the passage I88, a pressure control or relief valve I (Fig. 1) is connected to passage I88 by a conduit I26 and is connected to a reservoir IT! by a conduit I28. The pump casing I8 is also connected to the reservoir by a drain conduit I29. The showing, however, is diagrammatic in that in operating the pump it is contemplated that the casing III will be substantially filled with an operating fluid, such as oil. Thus, if a supplementary reservoir I2'I is used, it will be a closed reservoir if located below the pump, but may be anopen reservoir if located at a suitable elevation alongsideor above the pump. A drain I38 is provided in the casing 82 to drain off leakage fluid "reachthe servo-control mechanism passage I82. With the parts as shown in Fig. 9, they are in equilibrium with the ports93 in sleeve 8'! closed by the piston valve 82 (with the exception of a small amount of leakage past the -valve).' The control fluid in passage 95 is then trapped and maintained therein and holds the piston 8| and Wobbler I! in their adjusted positions. to the pressure of the fluid discharged from the The piston 86 is continuously subjected main pump and in the event this pressure rises, the piston 86 is moved to the right in the bore 84 and through the rod 96, forces the valve piston 92 to the right to a position as shown in Fig. 8.

Fluid'from the passage 95 and cylinder 3I is then permitted to discharge through ports 93 to the bore of sleeve 81 to the left of piston valve 92 and drain back into the pump casing I81 This release of pressure from the Wobbler piston 3I permits the springs I2 to move the tubular control member I8 to the left (Fig. 1) and swing the Wobbler to a reduced stroke position nearer neutral. This adjustment of the Wobbler swings the lever 88 in a clockwise direction so that the upper bifurcated end thereof moves the s1eeve8'I to the right until the ports 93 are closed by piston valve 92. During the time this takes place, the quantity of the fluid discharged from the pump is reduced and, therefore, the pressure thereof is reduced, so that piston 86 can move back to its original position of Fig. 9 under the influence of the pressureof the control fluid from passage I88 against the right hand end of sleeve 81. The lever 88 and other parts also return to the positions shown in Fig. 9.

When it is desired to increase the quantity of the fluid discharged by the main pump, the actuator I86 is moved to move piston I04 to the left. This causes a corresponding movement of piston 89 and piston valve 92, toward the left to a position as shown in Fig. 18. Control fluid from passage I88 can then pass through the sleeve 81, the ports 93, groove 94 and passage 95 to cylinder 3| and actuate piston 3I to increase the pump stroke, overcoming the springs I2. As control member 18 moves toward the right (Fig. 1), the lever 88 pivots counter-clockwise under influence of the sleeve 81 which is moved to- Wards the left (Fig. 10) by the control fluid until the valve 92 closes the ports 98 in the sleeve. The parts have then reached positions similar to those shown in Fig. 9 wherein they are in equilibrium.

The collar 91, which is fixed on the rod 96, is provided with a plurality of ports I38 to permit fluid to flow therethrough. This collar functions to prevent flutter or hunting of the servo valve mechanism and to limit the movement of the control .rod 96 and the associated pistons 86 and 89 relatively to the bifurcated upper end of the lever 88. Thus, if the piston 89 is moved towards the left from the position shown in Fig. 9, such movement is limited by engagement of the collar 91 with the upper end ton 86, engagement of the collar with a shoulder I3I on the sleeve 81 limits the movement of the rod relatively to the sleeve.

To decrease the output of the main pump, the actuator I86 is moved to the right to move piston I 84 to the right (Fig. 1) and thereby decrease the pressure in the passage I82. This permits the pressure on the piston 86 to move the pistons 86 and 89 toward the right and to uncover the j ports 93, as shown in Fig. 8. Control fluid'from passage then passes through the ports 93, the interior of sleeve 81 and the passage I28 and retmits'the Wobbler H to turn counterclockwise (Fig. 1 under action of the spring I2. The lever 80 then pivots in a clockwise direction (Fig. -8) and moves the sleeve 81 toward the right to close theports 93 as the Wobbler reaches its .new

position.

The piston and cylinder device H34, I03 has been illustrated diagrammatically in .Fig. l to represent a simple form of device for varying the pressure in the passage I02. As shown, the

. .fledbymeans interposed in the connection I05.

For example, the throttle I86 may control the adjustment of a governor responsive to engine speeds .and the governor, together with an altitude or air pressure operated device, function jointly to control the pressure in the passage ,1 claim:

I. A pump comprising, in combination, a casing provided with an inlet and an outlet, means forming a plurality of cylinders annularly arranged, pistons in said cylinders, a drive shaft, means for converting rotary movement of the shaft into reciprocatory movement of the pistons, means forming a cylindrical valve chamber having pairs of opposed ports with the ports of each pair being substantially alined with each other, one port of each pair communicating with a cylinder and the other communicating with the pump outlet, and valve means for alternatively connecting the cylinder ports with the inlet and for controlling separately and in repeated sequence the flow of fluid from one to the other port of each of said pairs of ports, said valve means comprising an annular valve member having valve ports therein, one associated independently with each of said pair of ports, eccentric means driven by the shaft for imparting to the Y valve member a gyratory movement and means for, preventing rotary movement thereof.

' 2. A pump comprising, in combination, a casing provided with an inlet and an outlet, means ,forming a plurality of cylinders, pistons in said cylinders, a drive shaft, means for converting rotary movement of the shaft into reciprocatory movement of the pistons, means forming a valve chamber having pairs of opposed ports with the ports of each pair being substantially alined with each other, one port of each pair communicating with a cylinder and the other communicating with the outlet, and valve means driven by said shaft for alternately connecting the cylinder ports with the inlet and for controlling separately and in repeated sequence the flow of fluid from one to the other port of each of said pairs of ports.

3. A pump as defined in claim 2 wherein said valve means comprises an annular valve member having valve ports therethrough, one associated independently with each of said pairs of ports,

converting rotary movement of the shaft into f8 reciprocatory-movement of the pistons, means forming avalvechamber having pairs of opposed ports with the portsof each pair being substantially alined with each other, one port of each pair communcating with a cylinder and the other communicating with the outlet, an annular valve member for alternately connecting the cylinder ports with the inlet and for controlling separately and in repeated sequence the flow of fluid from one to the other of each of said pairs of ports, and means for actuating said valve member comprising an eccentric pin on said shaft engaging a central bore in the valve member, a pair of shafts rotatably mounted in the casing and parallel to saiddrive shaft and eccentric pins-on said shafts engaging eccentric bores in said valve member.

5. A pump as defined in claim 4 wherein said annular valve member has valve ports therein, one associated] independently with each of said pair of ports.

6. A fluid pump comprising, in combination, a casing, a drive shaft rotatably mounted in the casing, a plurality of main piston and cylinder devices, inlet and. outlet ports, means for controlling the flow of fluid into and out of the cylinders of said devices including a wheel-like valve, eccentric means on said drive shaft for actuating said valve, eccentric means on shafts parallel to said drive shaft and engaging said valve to restrain it against rotary movement, means driven by said shaft for actuating the pistons through their pressure strokes, means for returning the pistons through their suction strokes comprising auxiliary piston and cylinder devices associated one with each of said main piston and cylinder devices, and means for maintaining fluid under pressure in said auxiliary cylinders comprising. means interconnecting the auxiliary cylinders in a substantially closed circuit, an auxiliary pump device operable to pump a lubricating liquid to said axiliary piston and cylinder devices, and means for controlling the pressure of said lubricating liquid.

'7. A fluid pump comprising, in combination, a casing, a drive shaft rotatably mounted in the casing, a plurality of piston and cylinder devices,

inlet and'outlet ports, means for controlling the flow of fluid into and out of the cylinders of said devices including a wheel-like valve, a first eccentric means on said drive shaft for actuating said valve, a second eccentric means on a shaft parallel to said drive shaft and engaging said valve to restrain it against rotary movement,

means driven by said shaft for actuating the pistons, and means for causing said second eccentric means to rotate in synchronism with the first eccentric means.

8. .A fluid pump comprising, in combination, a plurality of main piston and cylinder devices, means for controlling independently the flow of fluid into and out of each of the cylinders of said devices, means for actuating the pistons through their pressure strokes, means for return- .ing the pistons through their suction strokes a passage connecting theoutlet of said auxiliary pump with said circuit, and means for governing the pressure of the fluid in said cylinders.

9. A pump comprising, in combination, a number of piston and cylinder devices, which number is a multiple of three, means for reciprocating the pistons relatively to the cylinders in repeated predetermined sequence, means forming inlet and discharge ports for the cylinders and including a separate discharge port for each cylinder, valve means for controlling the inlet and discharge of fluid to and from the cylinders and means providing outlet ports for the pump with one outlet port for each three discharge ports and means connecting each outlet port to discharge ports equally spaced apart in the predetermined sequence of operation of the pistons.

10. A pump comprising, in combination, a plurality of piston and cylinder devices, means for reciprocating the pistons relatively to the cylinders in repeated predetermined sequence, means forming inlet and discharge ports for the cylinders and including a separate discharge port for each cylinder, valve means for controlling the inlet and discharge of fluid to and from the cylinders and means providing outlet ports for the pump and means connecting each outlet port to a plurality of discharge ports equally spaced apart in the predetermined sequence of operation of the pistons.

11. A pump comprising, in combination, a plurality of equally spaced and annularly arranged piston and cylinder devices, means for reciprocating the pistons relatively to the cylinders in repeated predetermined sequence, means forming inlet and discharge ports for the cylinders and including a separate discharge port for each cylinder, valve means for controlling the inlet and discharge of fluid to and from the cylinders and means providing outlet ports for the pump with one outlet port connected to a plurality of discharge ports which are equally spaced apart angularly in the predetermined sequence of operation of the pistons.

12. A pump comprising, in combination, acasing provided with an inlet and an outlet, a drive shaft rotatably mounted in the casing, a plurality of piston and cylinder devices for pumping a substantially non-lubricating fluid from the inlet to the outlet, valve means for controlling independently the flow of such fluid from the inlet into and out of the cylinders of said devices and to said outlet, means driven by the shaft for actuating the pistons through their pressure strokes, means for returning the pistons through their suction strokes comprising side wall chambers associated one with each of the cylinders of said piston and cylinder devices, fluid conducting means interconnecting said chambers in a substantially closed circuit, means for maintaining said chambers and circuit filled with lubricant under pressure comprising an auxiliary pump for pumping fluid lubricant and a passage connecting the outlet of said auxiliary pump with said circuit, and a reduced portion on each of said pistons forming an auxiliary piston located in each one of said chambers and constantly exposed to the pressure generated by- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,020,774 Nilson Mar. 19, 1912 1,817,063 Carrie et a1 Aug. 4, 1931 1,905,913 Kopp Apr. 25, 1933 1,946,510 Truesdell Feb. 13, 1934 1,981,757 Smith et a1 Nov. 20, 1934 2,081,270 Edmundson et a1. May 25, 1937 2,177,097 Doe Oct. 24, 1939 2,193,612 Alden Mar. 12, 1940 2,232,976 Schmied Feb. 25, 1941 2,265,232 Hoffer Dec. 9, 1941 2,285,476 Wahlmark June 9, 1942 2,331,046 Robinson Oct. 5, 1943 2,331,694 Jeffrey Oct. 12, 1943 2,369,134 Cameron Feb. 13, 1945 2,383,092 Wahlmark Aug. 21, 1945 2,403,371 Ifield July 2, 1946 2,470,220 Mott May 17, 1949 

